Compressed video data processing with conversion of image compression format

0001This is a divisional application of Ser. No. 08/945,923, filed Nov. 21, 1997 now U.S. Pat. No. 6,516,135, which is a 371 of PCT/JP96/02894, filed Oct. 4, 1996.

TECHNICAL FIELD

0002The present invention relates to a system which processes compressed video data of different compression formats and to an apparatus for recording and reproducing compressed video signals of different compression formats.

BACKGROUND ART

0003In a television broadcasting station, digital video cassette recorders are used by reporters to gather news materials or the like. Then, records in the digital video cassette recorders are reviewed and edited for broadcasting.

0004The records are transferred to a server including a hard disk or the like having a high storage capacity. Once the data are stored in the server, they can be assessed by any computer connected to the server. It is desired in a television broadcasting station to broadcast the latest news. Therefore, it is required to transfer the records gathered in the recorder to the server as fast as possible.

0005Video data without compression can be transmitted between a digital video cassette recorder and a server. On the other hand, when compressed video data are transmitted, the data can be transferred if the data compression format of the digital video cassette recorder is the same as that of the main server. However, the compression format of video data such as DV format of a digital video cassette recorder is usually different from the compression format of a server having a format such as MPEG standard. Therefore, a format converter for converting data compression format is needed between the digital video cassette recorder and the server. However, if the transfer speed of the server is normal speed, the compressed digital video data can be transferred only at the normal speed from the digital video cassette recorder. Therefore, speed cannot be increased even if the recorder can reproduce the data at a faster speed. It is desirable to construct a system which can deal with video data at a fast speed even if various data compression formats are used therein.

SUMMARY OF THE INVENTION

0006An object of the present invention is to provide a compressed video data processing system and an apparatus therefor which can satisfy compatibility of compressed digital video data of two or more different image compression formats.

0007Another object of the present invention is to provide a compressed video data processing system and an apparatus therefor which can record or reproduce compressed video data at a high speed even if conversion between two or more different image compression formats are processed.

0008In one aspect of the invention, a compressed video data processing system comprises a digital video cassette recorder for recording and reproducing video data according to a first image compression format, a first recording and reproducing device as a local server, and an image format converter connected between the digital video cassette recorder and the first recording and reproducing device. Further, the first recording and reproducing device as a local server is connected to a second recording and reproducing device as a main server. The first and second recording and reproducing devices record and reproduce compressed digital video data according to a second image compression format different from the first image compression format. The image format converter converts compressed digital video data between the first image compression format and the second image compression format. The second recording and reproducing device may be accessed by computers through a network. By providing the first recording and reproducing device between the image format converter and the second recording and reproducing device, the second recording and reproducing device can operate normally even when accessed by many computers.

0009In another aspect of the invention, a compressed video data processing system comprises a digital video cassette recorder, a first recording and reproducing device as a local server connected to the digital video cassette recorder, a second recording and reproducing device as a main server, an image format converter connected between the first and second recording and reproducing device. The digital video cassette recorder and the first recording and reproducing device record and reproduce video data according to a first image compression format, while the second recording and reproducing device record and reproduce video data according to a second image compression format. The image format converter converts compressed digital video data between the first and second image compression formats. Compressed video data are transferred between the digital video cassette recorder and the first recording and reproducing device at a first transfer speed, while compressed digital video data are transferred in a network transmission format between the first and second recording and reproducing devices through the image format converter at a second transfer speed. The first recording and reproducing apparatus can record and reproduce data at either of the first and second transfer speeds. Then, even if video data of the first and second image compression formats are not compatible with each other, compressed digital video data according to the first image compression format can be converted to those according to the second one, and vice versa. Thus, video data of different compression formats can be used easily in a single system. The first transfer speed can be determined independently of the second transfer speed. It is preferable that the second transfer speed is faster than the first transfer speed in order to transfer the data in the digital video cassette recorder at a high transfer speed in a form accessed in the first recording reproducing device.

0010Preferably, the image format converter may support a plurality of conversion processes between the first image compression format and one of a plurality of the second image compression formats for the main server. In the image format converter, a format detector detects the second image compression format and selects one of the conversion processes automatically according to the second image compression format detected by the image format converter. Thus, a user can use video data without knowing the image compression format.

0011In order to support a plurality of the first image compression formats, a plurality of combinations of the first recording and reproducing device and the compression format converter are preferably provided, each of the combinations corresponding to one of the plurality of the first image compression formats. Then, compressed digital video data according to the first image compression format of two or more different conversion speeds can be converted to each other. Preferably, the first recording and reproducing device comprises a plurality of input/output ports for compressed digital video data according to the first image compression format. Then, a plurality of compressed digital video data according to the first image compression format can be output or input efficiently. Preferably, the second recording and reproducing device comprises a plurality of input/output ports for compressed digital video data according to the second image compression format. Then, a plurality of compressed digital video data according to the second image compression format can be output or input efficiently.

0012Components in the system can be integrated as an apparatus. For example, a compressed video data processing apparatus comprises the digital video cassette recorder, the first recording and reproducing device and the image format converter. In a different example, a compressed video data processing apparatus comprises the first recording and reproducing device and the image format converter. Thus, a user can deal with video data easily without knowing conversion of image compression format. In these examples, the digital video cassette recorder is connected to the apparatus as an external component.

0013An advantage of the present invention is that the second recording and reproducing device as a main server can operate normally when video data of the first image compression format different from the image compression format thereof are recorded or reproduced after conversion of the image compression format.

0014Another advantage of the present invention is that video data can be transferred at a fast speed to the first recording and reproducing device.

0015A further advantage of the present invention is that a system can comprise components of various image compression formats.

BRIEF DESCRIPTION OF THE DRAWINGS

0016These and other objects and features of the present invention will become clear from the following description taken in conjunction with the preferred embodiments thereof with reference to the accompanying drawings, wherein:

0017<figref idref="DRAWINGS">FIG. 1</figref> is a block diagram of a video data processing system of a first embodiment according to the invention;

0018<figref idref="DRAWINGS">FIG. 2A</figref> is a block diagram of one part of the image format converter, and <figref idref="DRAWINGS">FIG. 2B</figref> is a block diagram of another part of the image format converter;

0019<figref idref="DRAWINGS">FIG. 3</figref> is a block diagram of a video data processing system of a second embodiment according to the invention;

0020<figref idref="DRAWINGS">FIG. 4A</figref> is a block diagram of one part of the image format converter, and <figref idref="DRAWINGS">FIG. 4B</figref> is a block diagram of another part of the image format converter;

0021<figref idref="DRAWINGS">FIG. 5</figref> is a block diagram of an apparatus for video data processing according to the invention;

0022<figref idref="DRAWINGS">FIG. 6</figref> is a block diagram of a VCR/network according to an example of the apparatus shown in <figref idref="DRAWINGS">FIG. 5</figref>;

0023<figref idref="DRAWINGS">FIG. 7</figref> is a block diagram of an apparatus for video data processing according to the invention; and

0024<figref idref="DRAWINGS">FIG. 8</figref> is a block diagram of a VCR/network according to an example of the apparatus shown in <figref idref="DRAWINGS">FIG. 7</figref>.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

0025Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, <figref idref="DRAWINGS">FIG. 1</figref> shows a video data processing system of a first embodiment according to the invention. In the system, a digital video cassette recorder <b>10</b> is connected through an image format converter <b>12</b> as an interface to a first recording and reproducing apparatus <b>14</b> having a large capacity storage device such as a hard disk and operating as a local server. The image format converter <b>12</b> converts a first image compression format (for example, DVCPRO as a kind of DV format), of video data of the digital video cassette recorder <b>10</b> to a second image compression format (for example, Motion-JPEG) of the first recording and reproducing apparatus <b>14</b>, and vice versa. The first recording and reproducing apparatus <b>14</b> is connected through a network to a second recording and reproducing apparatus <b>16</b> having a large storage capacity device such as a hard disk and operating as a main server. Compressed video data are transmitted between the two apparatuses <b>14</b> and <b>16</b> in a network transmission format. The second recording and reproducing apparatus <b>16</b> is connected through a network to a plurality of external recording and reproducing apparatuses, and it may be accessed by a plurality of other image processors. The first recording and reproducing apparatus <b>14</b> is controlled by a first controller <b>18</b>, while the second recording and reproducing apparatus <b>16</b> is controlled by a second controller <b>20</b>. A main controller <b>22</b> comprising a personal computer, a monitor, a keyboard and the like controls the digital video cassette tape recorder <b>10</b> and the first and second controllers <b>18</b> and <b>20</b> in the total system by using control signals sent in serial transmission of RS 422A standard or the like. The controllers <b>18</b>, <b>20</b> and <b>22</b> are known to a person skilled in the art, and they are not explained here further.

0026In the video data processing system shown in <figref idref="DRAWINGS">FIG. 1</figref>, digital video data of a moving picture of the first image compression format (for example, DVCPRO) are recorded and reproduced by the digital video cassette recorder <b>10</b> at normal speed. The image format converter <b>12</b> converts the received video data to video data according to the second image format without compression at normal speed. Then, the first recording and reproducing apparatus <b>14</b> as a local server stores the video data according to the second image format. It can edit video data of the moving picture. Then, the video data are transferred to the second recording and reproducing apparatus <b>16</b> as a main server, so that the video data can be accessed by other computers through the network. The two recording and reproducing apparatus <b>14</b> and <b>16</b> can process video data of the same image compression format.

0027In this system, when video data recorded in the digital video cassette recorder <b>10</b> is transferred to the first recording and reproducing apparatus <b>14</b>, it is required that the video data has to be processed at the normal speed for converting the image compression format. Because the first recording and reproducing apparatus <b>14</b> as the local server is provided between the digital video cassette recorder <b>10</b> and the second recording and reproducing apparatus <b>16</b> as the main server, the main server operates normally even when it is accessed by many computers connected to the main server. Then, the video data can be transmitted normally to and from the digital video cassette recorder <b>10</b>.

0028Next, the components <b>10</b>–<b>22</b> in the image processing system shown in <figref idref="DRAWINGS">FIG. 1</figref> are explained. The digital video cassette recorder <b>10</b> records compressed digital video data of the first data compression format such as DVCPRO standard in a digital video cassette and reproduces compressed digital video data recorded in a digital video cassette with the first image compression format at normal speed.

0029The image format converter <b>12</b> receives compressed digital video data of the first image compression format reproduced at normal speed received from the digital video cassette recorder <b>10</b> and converts them to digital component serial data of SMPTE 259M standard without compression. On the other hand, it converts digital component serial data of SMPTE 259M standard without compression to compressed digital video data of the first image compression format. Details of the image format converter <b>12</b> will be explained later with reference to <figref idref="DRAWINGS">FIGS. 2A and 2B</figref>.

0030The first recording and reproducing apparatus <b>14</b> includes a large capacity storage device such as a hard disk drive and operates as a local server. The apparatus <b>14</b> converts digital component serial data of SMPTE 259M standard received from the image format converter <b>12</b> to video data of a second image compression format such as Motion-JPEG and stores them. It can edit the stored data. Further, the compressed digital video data according to the second image compression format is sent to the second recording and reproducing apparatus <b>16</b> in a network transmission format such as ATM format or SDDI format. On the other hand, it can store compressed digital video data according to the second image compression format received from the second recording and reproducing apparatus <b>16</b> in the network transmission format. It reproduces video data as digital component serial data according to SMPTE 259M standard and sends them to the image format converter <b>12</b>.

0031The second recording and reproducing apparatus <b>16</b> includes a large capacity storage device such as a hard disk drive and operates as a main server. The apparatus <b>14</b> stores as-received digital video data compressed according to the second image compression format received in the network transmission format from the first recording and reproducing apparatus <b>14</b>. It also transmits the digital video data of the second image compression format through the network to other recording and reproducing apparatuses operating as main or local servers. When compressed digital video data stored in the recording and reproducing apparatus <b>16</b> are used, a processing reverse to the above-mentioned one is carried out.

0032The image format converter <b>12</b> will be explained here. <figref idref="DRAWINGS">FIG. 2A</figref> shows an example of one part of the image format converter <b>12</b> for converting compressed digital video data of the first image compression format to digital component serial signals of SMPTE 259M standard. A digital data expansion circuit <b>30</b> expands compressed digital video data to non-compressed data. A first converter <b>32</b> converts the non-compressed data to digital composite signals. A second converter <b>34</b> converts the digital composite signals to 4:2:2 component signals. A third converter <b>36</b> converts the 4:2:2 component signals to digital component serial data of SMPTE 259M standard. In a modified example, the first converter <b>32</b> converts the non-compressed data to 4:1:1 component signals, and the second converter <b>34</b> converts the 4:1:1 component signals to 4:2:2 ones.

0033<figref idref="DRAWINGS">FIG. 2B</figref> shows an example of another part of the image format converter <b>12</b> for converting digital component serial signals of SMPTE 259M standard to compressed digital video data of the first image compression format. A fourth converter <b>40</b> converts digital component serial data of SMPTE 259M standard to 4:2:2 component signals. A fifth converter <b>42</b> converts the 4:2:2 component signals to digital composite signals. A sixth converter <b>46</b> converts the digital composite signals to video data. A digital data compression circuit <b>48</b> compresses the video data to compressed digital data. In a modified example, the fifth converter <b>42</b> converts the 4:2:2 component signals to 4:1:1 component signals, and the sixth converter <b>46</b> converts the 4:1:1 component signals to video data.

0034One problem of the above-mentioned video data processing system of the first embodiment is that the transfer speed of video data from the digital video cassette recorder <b>10</b> to the first recording and recording apparatus <b>14</b> cannot be increased because the image compression format has to be converted by the converter <b>12</b>. The conversion of image compression format is needed because video data in the video cassette recorder <b>10</b> cannot be accessed by a computer or a server until the data compression format thereof is converted to the second data compression format. In the conversion, the transfer speeds of the compressed digital video data of the different image compression formats have to be kept the same. Therefore, if the transfer speed of the recording and reproducing apparatus <b>16</b> is normal speed, the compressed digital video data can be transferred only at normal speed. Therefore, the speed cannot be increased. Then, it is desirable to provide a video data processing system where video data can be transmitted fast between a digital video cassette recorder and a recording and reproducing apparatus processing the video data. Another problem of the system is that video data is deteriorated at the conversion of image compression format before they are edited in the first recording and reproducing apparatus <b>14</b>.

0035<figref idref="DRAWINGS">FIG. 3</figref> shows a block diagram of a video data processing system of a second embodiment according to the invention which solve the above-mentioned problems. In contrast to the system of the first embodiment shown in <figref idref="DRAWINGS">FIG. 1</figref>, positions of a first recording and reproducing apparatus <b>102</b> and an image format converter <b>104</b> are different from the counterparts of the first embodiment. In the system shown in <figref idref="DRAWINGS">FIG. 3</figref>, a digital video cassette recorder <b>100</b> is connected to a first recording and reproducing apparatus <b>102</b> having a large capacity storage device such as a hard disk and operating as a local server. The first recording and reproducing apparatus <b>102</b> is connected through an image format converter <b>104</b> as an interface to a second recording and reproducing apparatus <b>106</b> having a large storage capacity device such as a hard disk and operating as a main server. The image format converter <b>104</b> converts video data format, a first image compression format (for example, Motion-JPEG), of video data in the first recording and reproducing apparatus <b>102</b> to a second image compression format (for example, DVCPRO). The second recording and reproducing apparatus <b>106</b> is connected through a network to a plurality of recording and reproducing apparatuses. Thus, the second recording and reproducing apparatus <b>106</b> may be accessed by a plurality of other computers. The first recording and reproducing apparatus <b>102</b> is controlled by a first controller <b>108</b>, while the second recording and reproducing apparatus <b>106</b> is controlled by a second controller <b>110</b>. A main controller <b>112</b> comprising a personal computer, a monitor, a keyboard and the like controls the digital video cassette tape recorder <b>100</b> and the first and second controllers <b>108</b> and <b>110</b> with control signals sent in serial transmission according to RS <b>422</b>A standard. The controllers <b>108</b>, <b>110</b> and <b>112</b> are known to a person skilled in the art, and they are not explained here further.

0036In the system explained above, video data of two or more different image compression formats are recorded and reproduced independently of transfer speed. The image transfer can be performed in two directions. For example, a user can transfer video data in a digital video cassette at four times speed in the system as if he or she operates a single recording and reproducing apparatus having a large capacity storage device of a single image compression format.

0037Next, the components <b>100</b>–<b>106</b> in the image processing system shown in <figref idref="DRAWINGS">FIG. 3</figref> are explained. The digital video cassette recorder <b>100</b> records and reproduces compressed digital video data of a first image compression format (for example, DVCPRO) at four times speed. The recorder <b>100</b> records compressed digital video data of the first data compression format in a digital video cassette and reproduces compressed digital video data recorded in a digital video cassette with the first image compression format.

0038The first recording and reproducing apparatus <b>102</b> has a large capacity storage device such as a hard disk drive and it operates as a local server. The large capacity storage device is not limited to a hard disk drive. For example, it may comprise a semiconductor memory having a large capacity. The apparatus <b>102</b> is connected between the digital video cassette recorder <b>100</b> and an image format converter <b>104</b> and it is controlled by a first controller <b>108</b>. The apparatus <b>102</b> can be operated at a plurality of speeds and it has a function of converting speed. It receives compressed digital video data according to the first image compression format by the digital video cassette recorder <b>100</b> at four times speed therefrom and records the data in the large capacity storage device. It reproduces compressed digital video data according to the first image compression format recorded in the large capacity storage device at normal speed. It can also reproduce compressed digital video data according to the first image compression format recorded in the large capacity storage device at four times speed and transmits them to the digital video cassette recorder <b>100</b>. The first recording and reproducing apparatus <b>102</b> also has a function of editing compressed digital video data of the first image compression format. In contrast to the system shown in <figref idref="DRAWINGS">FIG. 1</figref>, video data to be edited are not deteriorated because edition is performed before the conversion of image compression format.

0039In this example, recording and reproducing speeds are normal speed and four times speed. However, various combinations are possible such as normal speed and normal speed, four times speed and two times speed, two times speed and normal speed, and six times speed and normal speed.

0040The image format converter <b>104</b> is connected between the first large capacity recording and reproducing apparatus <b>102</b> and the second large capacity recording and reproducing apparatus <b>106</b> for converting digital image format. It receives compressed digital video data of the first image compression format from the large capacity recording and reproducing apparatus <b>102</b> and converts the digital compression format thereof to a second image compression format such as Motion-JPEG at normal speed. Further, it sends the digital image of the second image compression format to the second recording and reproducing apparatus <b>106</b> in a network transmission format such as asynchronous transfer mode (ATM) or SDDI format. On the other hand, it receives digital video data of the second image compression format from the second recording and reproducing apparatus <b>106</b> in a network transmission format and converts them to video data of the first image compression format to be sent to the first recording and reproducing apparatus <b>102</b>. The image format converter <b>104</b> will be explained in detail later with reference to <figref idref="DRAWINGS">FIGS. 4A and 4B</figref>.

0041The second recording and reproducing apparatus <b>106</b> has a large capacity storage device such as a hard disk and it operates as a main server. The large capacity storage device is not limited to a hard disk drive. For example, it may comprise a semiconductor memory having a large capacity. The apparatus <b>106</b> is connected to the image format converter <b>104</b>, and it stores as-received digital video data compressed according to the second image compression format in a network transmission format received from the image format converter <b>104</b>. On the other hand, it communicates through a network to other large capacity recording and reproducing apparatuses operating as main or local servers. It is controlled by the second controller <b>110</b>. It also transmits the digital video data of the second image compression format to other large capacity recording and reproducing apparatuses operating as main or local servers. It also sends compressed digital video data of the second image compression format through the converter <b>104</b> to the first one <b>102</b> in a network transmission format.

0042The image format converter <b>104</b> will be explained here further. <figref idref="DRAWINGS">FIG. 4A</figref> shows an example of a part of the image format converter <b>104</b> for converting compressed digital video data of the first image compression format such as DVCPRO to those of the second image compression format such as Motion-JPEG standard. A digital data expansion circuit <b>130</b> expands compressed digital video data to non-compressed data. A first converter <b>132</b> converts the non-compressed data to digital composite signals. A second converter <b>134</b> converts the digital composite signals to 4:2:2 component signals. A third converter <b>136</b> converts the 4:2:2 component signals to digital compression data of Motion-JPEG standard. In a modified example, the first converter <b>132</b> converts the non-compressed data to 4:1:1 component signals, and the second converter <b>134</b> converts the 4:1:1 component signals to 4:2:2 ones.

0043<figref idref="DRAWINGS">FIG. 4B</figref> shows an example of another part of the image format converter <b>104</b> for converting compressed digital video data of the second image compression format to compressed digital video data of the first image compression format. A fourth converter <b>140</b> converts compressed digital data to 4:2:2 component signals. A fifth converter <b>142</b> converts the 4:2:2 component signals reversely to digital composite signals. A sixth converter <b>144</b> converts the digital composite signals to video data. A digital data compression circuit <b>146</b> compresses the video data to compressed digital data of the first image compression format. In a modified example, the fifth converter <b>142</b> converts the 4:2:2 component signals to 4:1:1 component signals, and the sixth converter <b>144</b> converts the 4:1:1 component signals to video data.

0044Operation in this system is explained. When a moving picture as compressed digital video data is transferred to the recording and reproducing apparatus <b>106</b> as the main server, compressed digital video data recorded in a digital video cassette according to the first image compression format (DVCPRO) are reproduced by the digital video cassette recorder <b>100</b> at four times speed and recorded in the recording and reproducing apparatus <b>102</b> as the local server. It is a feature of this system that moving pictures recorded in a digital video cassette can be sent to the hard disk in the recording and reproducing apparatus <b>102</b> at a speed much faster than the normal speed used in the system shown in <figref idref="DRAWINGS">FIG. 1</figref>. If necessary, the picture data are edited by the recording and reproducing apparatus <b>102</b>.

0045When the data stored in the first recording and reproducing apparatus <b>102</b> are transferred to the second recording and reproducing apparatus <b>106</b>, the apparatus <b>102</b> reproduces the compressed digital video data according to the first image compression format at the normal speed different from the four times normal speed at the recorder <b>100</b>, and the image format converter <b>104</b> as an interface converts them to compressed digital video data according to the second image compression format (Motion-JPEG) at the normal speed and sends them to the recording and reproducing apparatus <b>106</b> in a network transfer format. Thus, the apparatus <b>106</b> stores the compressed digital video data according to the second image compression format. Thus, the compressed digital video data according to the first image compression format received at four times speed are converted to those according to the second image compression format recorded at normal speed.

0046On the other hand, when compressed digital video data stored in the second recording and reproducing apparatus <b>106</b> is transferred, data flow is reversed. Compressed digital video data stored in the second recording and reproducing apparatus <b>106</b> is reproduced at normal speed to be sent to the image format converter <b>104</b> as an interface. The image format converter <b>104</b> converts them to compressed digital video data according to the first image compression format (DVCPRO) at the normal speed and sends them to the first recording and reproducing apparatus <b>102</b> to be stored at the normal speed. Then, the first recording and reproducing apparatus <b>102</b> stores compressed digital video data according to the first image compression format at four times speed to be transferred to the digital video cassette recorder <b>100</b>. Thus, the recorder <b>100</b> records them at four times speed. Thus, the compressed digital video data according to the second image compression format reproduced at normal speed are converted to those according to the first image compression format to be sent at four times speed.

0047In the above-mentioned system, compressed digital signals from a recording apparatus such as a digital video cassette recorder can be received directly at the local server. Then, picture data in a digital video cassette recorder can be stored at a fast speed in the local server.

0048When compressed digital video data to be reproduced are converted and output, the speed of the output digital video data is determined independently of the speed of the compressed digital video data when they are reproduced. Then, when compressed digital recording data are converted and stored, the speed of the received digital video data is determined independently of the speed of the compressed digital video data when they are stored. Therefore, compressed digital video data can be input at a high speed. When compressed digital video data are converted and output, the transfer speed of the digital video data to be reproduced is determined independently of the transfer speed of the compressed digital video data when they are reproduced. Therefore, compressed digital video data can be output at a high speed.

0049By using the image format converter <b>104</b>, compressed digital video data according to the first data compression format and those according to the second data compression format having different transfer speeds can be converted to each other. Then, a single system for recording and reproducing compressed digital video data can deal with two kinds of compressed digital video data according to the first and second data compression formats through the video cassette recorder and the main server use video data of different image compression formats. Therefore, a system can be constructed without problems even if components of different compression formats are included. Further, a cost of a system is decreased where video data processors are provided for each image compression format.

0050In the above-mentioned embodiments, the first image compression format is DVCPRO, but it may be other image compression format used in a digital video cassette recorder and the like. The second image compression format is Motion-JPEG, but it may be MPEG2 format.

0051Further, in the above-mentioned embodiment, N times speed of the video data according to the first image compression format is four times speed (N=4), while M times speed that of the video data according to the second image compression format is normal speed (M=1). However, various combinations of the two speeds can be adopted. For example, N=1, and M=1. However, in order to transfer the picture images in a digital video cassette recorder <b>100</b> to the first recording and reproducing apparatus <b>102</b> at a fast speed, it is preferable that N≧M, or N≧2 and M≧1.

0052Further, the digital video cassette recorder <b>100</b> may be integrated with the first recording and reproducing apparatus (local server) <b>102</b>. <figref idref="DRAWINGS">FIG. 5</figref> shows an example of an equipment <b>300</b> wherein a digital video cassette recorder (VCR) <b>100</b>, a first recording and reproducing apparatus <b>102</b> with a controller <b>108</b> thereof, and an image format converter <b>104</b> are integrated. This equipment is connected to the second recording and reproducing apparatus <b>106</b> as a main server. The apparatus <b>102</b> operating as a local server has a large capacity storage device such as a hard disk drive. Because the video cassette recorder <b>100</b> is integrated with the first recording and reproducing apparatus <b>102</b>, a user can process picture video data in a digital cassette without knowing the plurality of image compression formats.

0053The first recording and reproducing apparatus <b>102</b> may have a plurality of input and output portions, and a plurality of digital video cassette recorders <b>100</b> may be connected thereto, as shown in <figref idref="DRAWINGS">FIG. 5</figref>. In such a system, one of them can transfer compressed digital video data selectively to the first recording and reproducing apparatus <b>102</b>. Dubbing may be performed between two of the plurality of digital video cassette recorders <b>100</b> through the first recording and reproducing apparatus <b>102</b>. Because a plurality of digital video cassette recorder <b>100</b> are integrated with the first recording and reproducing apparatus <b>102</b>, input and output of video signals can be performed efficiently for compressed digital video data according to a plurality of the first image compression formats. Thus, in a single video data processing apparatus, a user can process compressed digital video data according to the first and second image compression formats without knowing the difference in image compression format. Therefore, a disadvantage caused by a necessity of using a plurality of non-compatible image compression formats can be solved.

0054The second recording and reproducing apparatus <b>106</b> may have a plurality of input/output ports. Then, compressed digital video data can be input and output efficiently according to the second image compression formats.

0055Further, a plurality of the equipment <b>300</b> may be connected to the second recording and reproducing apparatus (main server) <b>106</b>, as shown in <figref idref="DRAWINGS">FIG. 5</figref>. In this case, each equipment <b>300</b> may correspond to a different image compression format. Then, dubbing can be performed between the plurality of digital video cassette recorders <b>100</b> having different image compression formats and different speeds.

0056<figref idref="DRAWINGS">FIG. 6</figref> shows an example of the equipment <b>300</b>. A digital video cassette producer (VCR) <b>302</b> records and reproduces compressed video signals. An audio-visual interface <b>304</b> sends output signals of the digital video cassette recorder <b>302</b> to an internal bus <b>306</b>. A hard disk interface <b>308</b> records input signals in the internal bus <b>306</b> to hard disk <b>310</b> and reproduces output signals from the hard disk <b>310</b>. A converter <b>312</b> converts input and output signals in the internal bus <b>306</b> to compression format of a main server <b>360</b>. A control terminal <b>314</b> receives a control signal from a detector <b>316</b> which detects the compression format in order to change the compression format in the converter <b>312</b>. The detector <b>316</b> analyzes signals from a network interface <b>318</b> to determine the compression format of the main server <b>360</b> and sends a control signal to the control terminal <b>314</b>. The network interface <b>318</b> interfaces input and output signals to and from the converter <b>312</b> to a network <b>340</b>. Signals are transferred through the network to and from the main server <b>360</b>. For example, if the digital video cassette recorder <b>302</b> comprises a digital video cassette recorder for a consumer use (DV format) and the compression format of the main server <b>360</b> is MPEG, the detector <b>316</b> checks the compression format of the main server <b>360</b> in a communication through the network and controls the converter according to the result. If the compression format of the main server <b>360</b> is checked to be MPEG, the compressed data in the digital video cassette recorder <b>302</b> are converted to data of MPEG to be recorded in the main server <b>360</b>. If the main server <b>360</b> comprises an MPEG system, ID signals are superposed in bit streams of MPEG. The detector <b>316</b> detects the ID signals and controls the control terminal <b>314</b> according to the result. Then, the converter <b>312</b> converts compressed signals of the digital video cassette recorder <b>302</b> of DV format to compressed signals of MPEG. A similar operation is performed if the compression format of the main server <b>360</b> is JPEG. Thus, signals can be interfaced with no problem even if the compression format of the recording and reproducing apparatus <b>310</b> is different from that of the main server <b>360</b>.

0057<figref idref="DRAWINGS">FIG. 7</figref> shows an example of another type of an equipment <b>400</b> wherein a first recording and reproducing apparatus <b>102</b> as a local server with a controller <b>108</b> thereof, and a converter <b>104</b> are integrated. The apparatus <b>102</b> operating as a local server has a large capacity storage device such as a hard disk drive This equipment <b>400</b> is connected between an external digital video cassette recorder <b>100</b> and the second recording and reproducing apparatus <b>106</b> as a main server.

0058<figref idref="DRAWINGS">FIG. 8</figref> shows an example of the equipment <b>400</b>. An external digital video cassette recorder (VCR) <b>402</b> for recording and reproducing compressed video signals is provided outside the equipment <b>400</b>. Video signals are input and output through an audiovisual interface <b>404</b> to another audiovisual interface <b>406</b> provided in the equipment <b>400</b>. The interface <b>406</b> sends output signals of the digital video cassette recorder <b>402</b> to an internal bus <b>408</b> in the equipment <b>400</b>. A hard disk interface <b>410</b> records input signals in the internal bus <b>408</b> to a hard disk <b>412</b> and reproduces output signals from the hard disk <b>412</b>. A converter <b>414</b> converts an image compression format of signals in the internal bus <b>408</b> to that of the main server (second recording and reproducing apparatus) <b>460</b> having a large capacity storage device such as a hard disk. A network interface <b>418</b> interfaces input and output signals to and from the converter <b>414</b> to a network <b>440</b>. Signals are transferred through the network <b>440</b> to and from them main server <b>460</b>. For example, if the digital video cassette recorder <b>402</b> comprises a digital VCR for a consumer use (DV format) and the compression format of the main server <b>460</b> is JPEG or MPEG, the compressed data in the VCR <b>402</b> are converted to data of JPEG or MPEG to be recorded in the main server <b>460</b>. Equipment other than a digital video cassette recorder may also be connected if the audiovisual interface <b>406</b> supports such equipment, for example SCSI interface, IEEE 1394, fiber channel or the like. Thus, video signals can be interfaced with no problem even if the compression format of the data in the hard disk <b>412</b> is different from that of the main server <b>460</b>.

0059Though compression formats used in the abovementioned embodiments are a format for a digital video cassette recorder (DV format) and JPEG/MPEG for computer use, other compression formats can also be used similarly such as DVCPRO format of digital video cassette recorder for professional use, or fractal or wavelet format.

0060Although the present invention has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.